1. Field of the Invention
The present invention relates to telecommunication networks and, more particularly, to a method and system for reporting events to subscribers in telecommunication networks.
2. Background of the Art
Telecommunication networks use various signaling systems for establishing calls between subscribers. At times, however, the networks may detect certain states or events that would prevent the networks from establishing calls between subscribers. These events may include, for example, when a called directory number is out of service, network lines are busy or down, a switching node experiences a problem, etc. In such instances, the networks instead report the detected events to the subscribers by playing prerecorded audible messages.
Specifically, when a subscriber places a call to another subscriber in a network, a switching node local to the calling subscriber receives a call request from the calling subscriber's device. The switching node then sends a route request to a signaling node in the network to determine a route for the call. If the signaling node determines a route, the signaling node returns to the switching node the directory number of the next node in the network through which the call must be routed. Otherwise, if the signaling node detects that the call cannot be established or routed such as when the called subscriber's directory number is out of service, the signaling node returns an error code to the switching node. The switching node then notifies the subscriber that the requested call cannot be established by playing a prerecorded audible message corresponding to the error code.
Although audible messages may be sufficient for reporting events to subscribers who use plain ordinary telephone service (POTS) telephone sets, such messages are not universally recognizable by all subscriber devices. For example, consider a subscriber who uses a telecommunications device for the deaf (TDD) to place calls to other subscribers in the network. When the network plays an audible message to report an event, neither the subscriber nor the TDD device would be able to recognize the message. Similarly, an application running in a desktop computer for dialing into, for example, a local Internet Service Provider (ISP) system cannot recognize audible messages received from the network or present such messages in a form that is recognizable to a subscriber.
In present wireline telecommunications networks, a wireline telephone number or directory number (DN) is associated with a fixed geographic location and is served by a single wireline switch. A wireless DN, however, is associated with multiple geographic locations and is served by any one of a number of wireless switches depending on the specific geographic location of the associated wireless device at the time a call is made. This portability of a wireless DN is one of the basic attributes of wireless telephony.
A home location register and visited location register in a telecommunications network provide seamless roaming when a call is placed to or from a wireless DN. A home location register is associated with a home wireless switch where a wireless DN resides (i.e., the wireless switch to which all incoming calls to the wireless DN are directed). A wireless device is located within its home area when the wireless device can directly communicate with its associated home wireless switch (i.e., located in the area covered by the home wireless switch).
A visitor location register is associated with a wireless switch currently serving a wireless device that is outside of its home area. A wireless device is outside of its home area (or roams) when the wireless device cannot directly communicate with the home wireless switch and instead communicates with another wireless switch, which is referred to as a visited wireless switch.
In telecommunication networks two connections must be established when a call is placed to a wireless DN whose associated wireless device is outside of its home area. In such instances, the telecommunications network first establishes a connection to the home wireless switch associated with the wireless DN. The home wireless switch then establishes a second connection to a visited wireless switch that currently serves the wireless DN. When errors, such as missing information, misrouted query and other process failures are encountered, a numerical error value is returned to the requester representing the reason for the failure.
There are multiple messages used in wireless intelligent networks (WIN) that route call requests from wireless subscribers or from users who use audible devices such as, plain ordinary telephone service (POTS) telephone sets, attempting to communicate with the wireless subscribers. These include, but are not limited to, the LocationRequest, RoutingRequest, OriginationRequest and TerminationRequest messages described in “Interim Standard 41” (IS-41). The IS-41 standard is described in “Radio Telecommunications Intersystem Operations,” ANSI/TIA/EIA/41-D-1997, which is incorporated herein by reference. Although used in different circumstances, each of these messages ultimately requests a Directory Number which to route the call requests.
As an illustration, FIG. 10 shows a block diagram of a conventional Telecommunication network (1000) implementing the LocationRequest, RoutingRequest messages. Telecommunications network 1000 comprises a wireline switch 1020, a home wireless switch 1040, a home location register (HLR) 1050, signal transfer points (STPs) 1060, 1087 and 1057, a visitor location register (VLR)1070, a visited wireless switch 1080, a wireline telephone 1010, antenna 1090, and a wireless device 1095.
Typically, a wireline subscriber using telephone 1010 initiates a call request by dialing the wireless DN associated with wireless device 1095, temporarily located in a visited system controlled by visited wireless switch 1080. The request is sent to wireline switch 1020 over existing connection 1000a, where it examines the DN to determine its status (resident or non-resident). When wireline switch recognizes the non-resident status of the number, it routes the request 1000b to Public switch Telephone Network/Interchange Carrier (PSTN/IXC) 1030 over existing connection 1000b. PSTN/IXC 1030 examines the dialed number and routes it to home wireless switch 1040, using existing connection 1000c. 
Home wireless switch 1040 recognizes the DN as one that it is not currently serving, and sends an IS-41 LocationRequest message 1000d to HLR 1050, possibly through STP 1057. HLR 1050 examines its database and determines that the wireless device 1095 is being served by VLR 1070, which is associated with the visited wireless switch 1080. HLR 1050 sends an IS-41 RoutingRequest 1000e to VLR 1070, possibly by way of STP 1060.
VLR 1070 consults its internal database and allocates a Temporary Local Directory Number (TLDN) from a pool of available numbers associated with visited wireless switch 1080 currently serving wireless device 1095. The TLDN is populated into the response to the RoutingRequest 1000e and sent back to HLR 1050 as RoutingRequest response 1000f, possibly by way of STP 1060.
HLR 1050 takes the TLDN from the RoutingRequest response 1000f and populates it into the response to the LocationRequest 1000d from home wireless switch 1040, as LocationRequest response 1000g. Home wireless switch 1040 examines the LocationRequest response 1000g and establishes the route to the TLDN by way of PSTN/IX 1035. The PSTN/IX 1035 establishes a route to the visited wireless switch 1070 and passes the call via connection 1000i. The visited wireless switch 1080 sends a RoutingRequest 1000j to VLR 1070 possibly through STP 1087, and receives a response 1000k containing a mobile identification number (MIN) previously associated with the TLDN populated into RoutingRequest response 1000f. The visited wireless switch 1070 then routes the call to the wireless device 1095 by way of antenna 1090 using internal routing 10001. Thus, wireline telephone 1010 is connected to wireless device 1095 by a voice path consisting of a subscriber line 1000a, wireline switch 1020, connection 1000b, PSTN/IX 1030, connection 1000c, home wireless switch 1040, connection 1000h, PSTN/IX 1035, connection 1000i, visited wireless switch 1080, internal connection 10001, and antenna 1090.
It should be noted that STPs 1057, 1060 and 1087 may represent one or more STPs that are required to perform the transfer of messages. Furthermore, the communications between VLR 1070 and HLR 1050, visited wireless switch 1080 and VLR 1070, and between home wireless switch 1040 and HLR 1050, may take place without STPs 1060, 1087 and 1057, respectively.
Event reporting (including error handling) occurs whereby an error code is returned in the response to either the RoutingRequest or LocationRequest (depending on the entity encountering the exception condition). This error would propagate back to the original requesting party, the home wireless switch 1040, which would map the event/error to one of the standard recordings already available on the switch. Examples of events that might be reported are Subscriber Not available [No Page Response], No Capacity [Resource Shortage] and Busy.
FIG. 11 shows a block diagram of a conventional Telecommunication network (1100) implementing the OriginationRequest message. Telecommunications network 1100 comprises a wireline switch 1180, a home location register 1160, signal transfer points (STPs) 1150 and 1147, a visitor location register 1140, a visited wireless switch 1130, a wireline telephone 1190, antenna 1120, and a wireless device 1110.
Typically, wireless device 1110 originates a call at visited wireless switch 1130 by way of antenna 1120 and existing internal connectivity 1100a. Visited wireless switch 1130 recognizes parameters previously provided by home location register (HLR) 1160, causing an origination trigger to be invoked, which locates a visited location register (VLR) associated with the visited wireless switch 1130. This results in an OriginationRequest 1100b to be sent to VLR 1140, possibly through STP 1147.
VLR 1140 passes the OriginationRequest 100b to HLR 1160, possibly by way of STP 1150. HLR consults its internal tables and routing information to determine if the dialed call is allowed, possibly substituting a different destination number into a OriginationRequest response 1100c. The OriginationRequest response 1100c is passed back to the visited wireless switch 1130 by way of VLR 1140 and possibly STPs 1150 and 1147.
It should be noted that STPs 1150 and 1147 may represent one or more STPs that are required to perform the transfer of messages. Furthermore, the communications between VLR 1140 and HLR 1160, and visited wireless switch 1130 and VLR 1140, may take place without STPs 1150 and 1147, respectively.
The visited wireless switch 1130 routes the call to the destination number returned in the OriginationRequest response 1100c by way of existing connection 1100d to PSTN/IX 1170. The call is routed by PSTN/IX 1170 to wireline switch 1180, where the destination number resides, by way of existing connection 1100e. Wireline switch 1180 routes the call to wireline telephone 1190.
The overall differentiation here from an ordinary wireless call is that each call made by the wireless device 1110 is validated by HLR 1160, and the actual destination connected to is that specified by HLR 1160 through the destination number contained in the OriginationRequest response 1100c, which may be the same or different from the number dialed by the wireless device 1110.
Analogous to the description of FIG. 10, event reporting (including error handling) occurs whereby an error code is returned in the response to the OriginationRequest. This error would propagate back to the original requesting party, the visited wireless switch 1130, which would map the event/error to one of the standard recordings already available on the switch. Examples of events that might be reported are No Capacity [Resource Shortage] and Unassigned Directory Number.
FIG. 12 shows a block diagram of a conventional Telecommunication network 1200 implementing the TerminationRequest message. Telecommunications network 1200 comprises a wireline switch 1220, PSTN network 1230, a home wireless switch 1240, a home location register 1250, STP 1257, a wireline telephone 1210, antenna 1260, and a wireless device 1270.
Typically, a wireline telephone 1210 attempts to place a call to wireless device 1270 by utilizing existing connection 1200a to wireline switch 1220. Wireline switch 1220 routes the call through existing connection 1200b to PSTN/IX 1230. PSTN/IX 1230, using existing connection 1200c, passes the call to home wireless switch 1240. Home wireless switch 1240 recognizes parameters previously provided by HLR 1250, causing a termination trigger to be invoked, which locates a HLR associated with the visited wireless switch 1230, in this case HLR 1250. Home wireless switch 1240 subsequently provides a TerminationRequest 1200d to HLR 1250, possibly through STP 1257.
HLR 1250 consults internal tables and routing information to determine if the dialed call is allowed, and possibly substitutes a different phone number into a TerminationRequest response 1200e. The TerminationRequest response 1200e is passed back to the home wireless switch 1240, possibly through STP 1257. The home wireless switch 1240 may then route the call to the wireless device 1270 by way of internal connection 1200f and antenna 1260. The advance described here is the ability of HLR 1250 to examine the call attempt to the wireless device 1270 and specify the actual termination directory number.
It should be noted that STP 1257 may represent one or more STPs that are required to perform the transfer of messages. Furthermore, the communications between home wireless switch 1240 and HLR 1250, may take place without STP 1257.
Similar to the description of FIGS. 10 and 11, event reporting (including error handling) occurs whereby an error code is returned in the response to the TerminationRequest. This error would propagate back to the original requesting party, the home wireless switch 1240, which would map the event/error to one of the standard recordings already available on the switch. Examples of events that might be reported are No Capacity [Resource Shortage] and Unassigned Directory Number.
With reference to the networks described in FIGS. 10–12, problems arise in returning the reason for the failure to the party that originated the call, enabling them to correct their actions, if possible, and retry their call. Current technology provides only for the requester to interpret the error value according to a standard definition and provide their own routing to an audible error message. Because of using only a fixed audible recording technology for the error report, automated and data-only calls may fail to provide usable information to the call originator. For example, an audible message has little value to a hearing impaired user attempting a call using a Telecommunications Device for the Deaf (TDD). Similarly, an application running in a desktop computer for dialing into, for example, a local Internet Service Provider (ISP) system cannot recognize audible messages received from the network or present such messages in a form that is recognizable to the wireless subscriber. With calls in a wireless intelligent network originating from multiple sources and performing requests for routing information from multiple sources, the problem of providing this information in a meaningful format for specific users grows geometrically with the size of the Intelligent Network (IN). Additionally, error sources that are not specific to the IN but may be meaningful to the applications cannot be reported without expanding the standard offering for the IN.
As yet another example, consider subscriber devices used in automotive telemetric or remote reading applications. In such applications, subscriber devices send and receive data from remote systems by automatically placing calls over existing networks. However, since these subscriber devices cannot process the audible messages that are reported by the networks, they cannot provide the subscriber with informative as to the cause of most communication failures. Furthermore, these subscriber devices cannot automatically take corrective actions in response to most communication failures. Corrective actions may include, for example, redialing a directory number when network lines are busy or dialing a different directory number when a previously dialed directory number is temporarily out of service. As the number of subscribers who use these and other devices that cannot process audible messages increases, the need for reporting network events in formats that subscriber devices can process grows accordingly.
Furthermore, even with respect to those users who use audible devices such as, plain ordinary telephone service (POTS) telephone sets, to communicate with wireless subscribers there is a need to provide audible messages in languages that both the users and subscribers can understand. For example, a Spanish speaking subscriber may wish to receive audible messages in Spanish, whereas a French speaking subscriber may wish to receive audible messages in French. The utility of this process recognizes that if a wireless subscriber utilizes a special data type (such as TDD), or language (such as French), for communication, then those who wish to communicate with the wireless subscriber will also be expecting the same format.